Carton corner construction



5. LIGHTER CARTON CORNER CONSTRUCTION Filed Nov. 22, 1945 IN V EN TOR.

Patented Jan. 16, 1945 UNITED STATES PATENT OFFICE CARTON CORNERCONSTRUCTION Stephen Lighter, Milwaukee, Wis.

Application November 22, 1943, Serial No. 511,211

2 Claims.

The present invention relates generally to improvements in the art oi!manufacturing cartons, boxes or the like, and relates more particularlyto improvements in the construction and operation of the corners forcollapsible cartons formed of cardboard or similar material.

The primary object of this invention is to provide a new and usefulcarton corner construction which is simple and durable in construction,and which also facilitates assembly and collapse of the cartons to whichit is applied.

Many different types of so-called collapsible or knock-down boxes orcartons have heretofore been proposed and used extensively for diversepurposes, and perhaps the majority of these prior cartons have been,formed of cardboard stock which is cut into unitary blanks properlyscored for convenient assembly and collapse by folding along the scorelines. During the formation of such boxes from cardboard stock, it isextremely desirable to utilize as little stock as possible for a cartonof predetermined size, while maintaining maximum strength and rigidityof the assembled structures; and it is moreover exceedingly desirable tobe able to assemble the receptacles quickly and conveniently in a mannerwhereby the assemblages will be automatically locked in assembledcondition. While many prior attempts have been made to produce suchself-locking carton assemblages, most of these prior devices are notcommercially satisfactory either because they are too complicated andcostly, or because they ton adapted to be formed of a single blank orsheet of material, and having in addition to the usual bottom andfoldable side and endwalls, improved corner structures and lockingdevices which obviate the above mentioned objectionable features anddifficulties.

Another specific object of the present invention is to provideanimproved carton corner which may be formed of relatively thincardboard stock or the like, to produce multiple reenforcement for thebox to which the corner assemblages are applied.

A further specific object of my present invention is to provide animproved automatic lock and reenforcement for each corner of a boxformed of a unitary blank of sheet material such as cardboard.

Still another specific object of this invention is to provide animproved carton comer construction which can be produced at moderatecost with minimum waste of stock, and which can be quickly andconveniently assembled to provide a strong and self-retaining boxassemblage.

ihese and other specific objects and adyantages of the invention will beapparent from the following detailed description.

A clear conception of the several features constituting my presentimprovement, and of the mode of constructing and of assembling a cartoncorner involving the invention, may be had by referring to the drawingaccompanying and forming a part of this specification wherein likereference characters designate the same or similar parts in the variousviews.

Fig. 1 is a plan view of a comer fragment of a blank for a collapsiblecarton, showing the same in collapsed or fiat condition, but cut andscored ready for folding;

Fig. 2 is a perspective view of the corner fragment of Fig. 1, with theside and end walls elevated approximately half-way;

Fig. 3 is another perspective view of the same co'rner fragment, showingthe side and end walls almost, but not fully erected;

Fig. 4 is still another perspective view of the corner fragment,depicting the side and end walls fully elevated or erected, and alsoshowing the corner construction almost assembled but not yet finallylocked;

Fig. 5 is an additional perspective view of the corner fragment,illustrating the corner construction in finally assembled and lockedcondition; and v Fig. 6 is an enlarged transverse section through theassembled corner showing the locking tongue in action.

While the invention has been shown and de scribed herein as having beenembodied in a single carton corner construction of specific dimensionsand having vertical walls, it is not my desire or intent to therebyunnecessarily restrict the scope or utility vof the improvement, and itshould be understood that more than one of the improved corners may beapplied to the same carton or box.

Referring to the drawing, the improved carton shown therein may beformed of a single blank of cardboard and comprises in general, a flatrectangular bottom I having side walls 8 and end walls Sfoldablyconnected to its edges along score lines IO, II respectively; atriangular corner section I2 foldably connected to the end edge of theside wall 8 along a score line l3; a second triangular corner section Itfoldably connected to the end edge of the end wall 9 along a score lineIt, and also being foldably connected to the first mentioned cornersection |2 along a diagonal score line IS; a third approximatelytriangular corner section i1 foldably connected to the free edge of thesecond corner section II along a score line l8 and having an integrallocking tab or tongue l9 projecting outwardly from an edge thereof andcooperable with an opening 20 formed at the lower edge portion of theside wall 8; and a triangular panel 2| from which the tongue is has beencut, and which is foldably connected to the adjacent edge of the thirdcorner section II along a score line 22.

All of the corner sections l2, I4, H, the bottom 1, the walls 8, 9, thepanel 2|, and the tongue I9 are formed integral with each other and froma single blank, and in order to avoid waste of stock when producingthese blanks, the corner sections l2, H, H and the panel 2| are allconfined within the square bounded by the score lines l3, l5 and by theimaginary intersecting extensions of the outer upwardly swinging edges23, 24 of the walls 8, 9 respectively. In order to insure proper foldingof the corner sections l2, M when the side and end walls 8, 9 are swunginto erect position, and in a structure wherein these walls are finallydisposed perpendicular to the bottom I, the inclination of the scoreline l8 and f the corresponding free edge 25 of the triangular section|2 should each be disposed at an angle of 40 relative to the adjacentscore lines I3, l5, and the fold line l6 should form an angle of 45 witheach of the lines l3, IS. The locking tongue |9 should not be scored andshould finally coact with the slot or opening 20 in the edge of the wall8, as shown in Fig, 6, so as to provide a firm lock for the assembledcorner; and while the panel 2| provides added strength andreeni'orcement for the assembled corner, this panel 2| may be omittedproviding the fold line 22 properly coacts with the score line 3 in thefinally erected assemblage as illustrated in Fig. 5. When the improvedcarton blanks have been properly cut and scored as shown in Fig. 1, theymay be stacked in compact rectangular piles, and the self-locking cornerassemblages may be applied to two or more corners of each blank. Inorder to erect or assemble a box from one of the blanks, it is onlynecessary to perform the several successive steps depicted in Figs. 2 toinclusive. During such assembly of a comer, the side and end walls 8, 9should be swung upwardly away from the bottom 1 about their respectivefold lines IO, N so as to cause the hingedly connected triangular cornersections l2, H to swing inwardly about their fold lines l3, l5respectively, as illustrated in Fig. 2. Continued erection of the sideand end walls 8, 9 will cause the corner sections i2, II to move towardoverlapping position and these sections l2, H should be simultaneouslypressed against the inner surface of the adjacent end-wall 9, see Fig.3. As the overlapping or superimposed triangular sections l2, ll

approach their final position against the end wall s. the slot 20 willbe opened; and the trian ular corner section II should be swung aboutthe fold line l8, inwardly and downwardly over the free edge 25 of thecomer section 2, as shown in Fig. 4. The panel 2| may be simultaneouslyfolded in a reverse direction about its hinge line 22 so as to cause thelocking tab or tongue l9 to project outwardly; and when the three cornersections I2, l4, H are finally pressed into snug superimposed positionagainst the inner surface of the end wall 9 as in Figs. 5 and 6, thetongue I! will snap into the slot 20 to firmly lock the corner inassembled position. This final positioning of the corner sections I2,I4, I I will materially reenforce the wall 9 at the corner, and willalso cause the panel 2| to hug the interior surface of the side wall 8thereby likewise reenforcing this wall at the carton corner; and inorder to dismantle or collapse the box, it is only necessary to withdrawthe tongue I! from the slot 20 and to reverse the operations abovedescribed.

From the foregoing detailed description, it will be apparent that mypresent invention provides an improved carton corner construction whichis simple, compact and sturdy in structure, and which is moreoveradapted for rapid and convenient assembly and dismantling. The improvedstruc are is also self-locking and provides strong reenforcement for thecorner of the carton to which it is applied, without undesirablyobstructing the interior of the box. The new comer construction may beapplied to any or all of the corners of a box, and besides eliminatingwaste of stock the corner structure utilizes the stock available withina rectangular blank to best advantage for reenforcing purposes. Whilethe panel 2| may be omitted, it does serve to reenforce the. wall 8, andthe corner section I! may also be widened at its outermost end in adirection toward the free edge 25 of the section I 2, if so desired. Theblanks utilized in the formation of the improved cartons may also beproduced of relatively thin cardboard stock and with the aid of simpleequipment, and since these blanks lie flat when collapsed, they may becompactly stacked for storage and shipment. The automaticallyfunctioning locking tongues I9 serve to maintain the corners inassembled condition while also retaining the triangular sections |2, l4,l1 and the panels 2| snugly superimposed and against the adjacent walls,and the improved boxes can be manufactured at moderate cost and haveproven highly satisfactory in actual use and are especially adapted forpackaging laundry or the like.

It should be understood that it is not desired to limit this inventionto the exact details of construction, or to the precise mode of assemblyand dismantling, herein shown and described, for various modificationswithin the scope of the appeirzided claims may occur to persons skilledin the ar Iclaim:

1. A carton formed ofa single blank having a bottom provided with sideand end walls foldably connected to the bottom and being disposableeither perpendicular to or flatly collapsed into the plane of thebottom, the adjacent end edges of said side and end walls being foldablyinterconnected by a set of three approximately triangular cornersections one of which is foldably connected to one of said wall edgesand another of which is likewise connected to the other or said walledges and to said first mentioned section while the third section isfoldably connected to said second mentioned section whereby said threesections are ioldable from flat position in the plane of said bottominto triple-ply substantially triangular formation lying flat againstone of said walls, a tongue projecting from an edge of said thirdsection and being insertible in a slot near the end edge of the wallwhich is not engaged by the folded corner sections so as to hold thethree superimposed sections snugly against the other wall and to lockboth walls inerected position, and a re-enforcing panel foldablyconnected to the edge of said third corner section from which the tongueprojects and being adapted to lie fiat against the slotted wall when thetongue engages the slot, the direct connected edges of the first andsecond triangular corner sections being disposed at 45 angles withrespect to the end edges of the walls when the blank is in flatcondition and the other swinging edges of these two sections beingdisposed at 40 angles relative to the end edges of their supportingwalls, and all three of the corner sections and the locking tongue andpanel being formed from the blank stock originally disposed within thecomer rectangle.

2. A carton formed of a single "blank having a bottom provided with sideand end walls foldably connected to the bottom and being disposableeither perpendicular to or flatly collapsed into the plane of thebottom, the adjacent end edges of saidvside and end walls being foldablyinterconnected by a set of three approximately triangular cornersections one of which is foldably connected to one of said wall edgesand another of which is likewise connected to the other of said walledges and to said first mentioned section while the third section isfoldably connected to said second mentioned section whereby said threesections are foldable from flat position in the plane of said bottominto triple-ply substantially triangular formation lying flat againstone of said walls, a tongue projecting from an edge of said thirdsection and being insertible in a slot near the end edge of the wallwhich is not engaged by the folded comer sections so as to hold thethree superimposed sections snugly against the other wall and to lockboth walls in erected position, the direct connected edges of the firstand second triangular corner sections being disposed at 45 angles withrespect to the end edges of the walls when the blank is in flatcondition and the other swinging edges of these tw sections beingdisposed at 40 angles relative to the end edges of their supportingwalls, and all three of the corner sections and the locking tongue beingformed from the blank stock originally disposed within the cornerrectangle.

STEPHEN LIGHTER.

